WILDERNESS & ENVIRONMENTAL MEDICINE, 26, 497–508 (2015) CASE SERIES California Sea Lion (Zalophus californianus) and Harbor Seal (Phoca vitulina richardii) Bites and Contact Abrasions in Open-Water Swimmers: A Series of 11 Cases Thomas J. Nuckton, MD, MS; Claire A. Simeone, DVM; Roger T. Phelps, MD From the Department of Medicine, California Pacific Medical Center, San Francisco, and the Department of Medicine, University of California, San Francisco, CA (Dr Nuckton); the Department of Medicine, Sutter Eden Medical Center, Castro Valley, CA (Drs Nuckton and Phelps); and the Department of Veterinary Science, The Marine Mammal Center, Sausalito, CA (Dr Simeone). Objective.—To review cases of bites and contact abrasions in open-water swimmers from California sea lions (Zalophus californianus) and harbor seals (Phoca vitulina richardii). Methods.—Open-water swimmers from a San Francisco swimming club were questioned about encounters with pinnipeds (seals and sea lions) that resulted in bites or contact abrasions. When possible, wounds were documented with photographs. Medical follow-up and treatment complications were also reviewed. Results.—From October 2011 to December 2014, 11 swimmers reported bites by a sea lion (n ¼ 1), harbor seal (n ¼ 7), or unidentified pinniped (n ¼ 3). Ten of the encounters occurred in San Francisco Bay; 1 occurred in the Eld Inlet, in Puget Sound, near Olympia, WA. None of the swimmers were wearing wetsuits. All bites involved the lower extremities; skin was broken in 4 of 11 bites and antibiotics were prescribed in 3 cases. One swimmer, who was bitten by a harbor seal, also had claw scratches. A treatment failure occurred with amoxicillin/clavulanate in another swimmer who was bitten by an unidentified pinniped; the wound healed subsequently with doxycycline, suggesting an infection with Mycoplasma spp. There were no long-lasting consequences from any of the bites. The majority of cases occurred at low tide, and bumping of the swimmer by the animal before or after a bite was common, but no clear tide or attack pattern was identified. Conclusions.—Bites and contact abrasions from sea lions and harbor seals are reported infrequently in open-water swimmers and typically involve the lower extremities. Because of the risk of Mycoplasma infection, treatment with a tetracycline is recommended in pinniped bites with signs of infection or serious trauma. Attempting to touch or pet sea lions or seals is inadvisable and prohibited by the Marine Mammal Protection Act. Swimmers should leave the water as soon as possible after a bite or encounter. Key words: swimming, animal bites, marine mammals, pinnipedia, California sea lions, harbor seals Introduction medical reports of bites in recreational swimmers are lacking. The popularity of open-water swimming continues to – In this case series we outline 11 encounters with increase,1 3 and swimmers are at risk of contact with pinnipeds in open-water swimmers during a 3-year period. marine life. Bites from pinnipeds (seals and sea lions) in Two types of pinnipeds, the California sea lion (Zalophus humans have been reported in the popular media4,5 and californianus; Figure 1) and the harbor seal (Phoca vitulina in online medical websites.6,7 One newspaper account richardii; Figure 2),arecommoninthewesternUnited reported that 14 swimmers were bitten by a single sea States and were involved in the encounters. When possible, lion in San Francisco Bay over the course of 4 days in wounds are documented by photographs. Medical follow-up November 2006.5 Pinniped bites and their complications and treatment complications are also discussed. have also been reported in the medical literature in hunters, divers, and marine mammal workers,8–18 but Methods Corresponding author: Thomas J. Nuckton, MD, MS, 6 Locksley Avenue, #8J North, San Francisco, CA 94122-3822 (e-mail: nuckton@ All cases involved swimmers from the San Francisco sutterhealth.org). Dolphin Swimming and Rowing Club. The organization, 498 Nuckton et al If the swimmer could not recall sufficient details about the animal involved, the animal was classified as an “unidentified pinniped.” Tide, water temperature, and other data for the time of each encounter were obtained from National Oceanic and Atmospheric Association websites.19,20 General data pertaining to regional rainfall, water salinity, and domoic acid concentrations were obtained from additional online and other sources.21–28 Results A synopsis of the cases is provided in the Table; additional case details are outlined in the supplemental Figure 1. California sea lion (Zalophus californianus). Photo: The Marine Mammal Center. Appendix. Both the Table and the Appendix provide reference to corresponding figures (Figures 3–7). established in 1877 and now with more than 1300 In all cases, swimmers were swimming without wet- members, is home to a large group of recreational suits. All bites occurred in the San Francisco Bay, with swimmers who swim in the San Francisco Bay year- the exception of 1 bite that occurred in the Eld Inlet, in round and without wetsuits. The authors of this report Puget Sound, near Olympia, WA (swimmer from San fi are also members or have working knowledge of the Francisco visiting the area). The rst pinniped encounter club. Tracking of pinniped encounters at the Dolphin in this series occurred in October 2011. The last Club began after the first encounter mentioned in this encounter was in August 2013, with no further encoun- report (October 2011) and continued through December ters noted through the end of 2014. Skin was broken in 4 2014. When cases came to the attention of the authors, cases (cases 1, 6, 7, and 8). Antibiotics were prescribed individual swimmers were approached for an interview. in 3 cases (cases 1, 7, and 8). Wound or blood cultures Each swimmer was asked to openly describe the were not obtained in any case. One swimmer (case 3), encounter to the best of his or her memory, without a who was bitten by a harbor seal, also had claw scratches. specific questionnaire or collection device. In general, A treatment failure occurred with amoxicillin/clavulanate the authors asked follow-up questions as needed regard- in another swimmer (case 8); the wound healed sub- ing the time and date of the encounter, the location of the sequently with doxycycline. Wound healing was com- encounter, the type of animal involved, the behavior of plete in all cases. both animal and swimmer during the encounter, the The water temperatures (range, 13.2ºC [55.8ºF] to 1 nature of the injury itself, treatment, and subsequent 15.7ºC [60.3ºF]) and air temperatures (range, 10.6 C 1 1 1 wound healing or complications. [51.1 F] to 16.6 C [61.9 F]) during the encounters did not appear to be atypical for San Francisco Bay or Puget Data were collected retrospectively, and swimmers 19 provided all information at their convenience, in person Sound. The majority of cases occurred at low tide, and or by e-mail, including information about treatment and bumping of the swimmer by the animal before or after a medical follow-up. Medical records were not reviewed. bite was common, but no clear tide or attack pattern was identified. Additional details pertaining to regional rain patterns,21,22 water salinity,19,23–26 and domoic acid concentrations in sampled shellfish26–28 can be found in the Appendix; no clear abnormalities in these varia- bles that were likely to have contributed to the pinniped encounters mentioned in this report were identified. Discussion From our data, unprovoked bites from pinnipeds in recreational swimmers appear to be relatively rare. Eleven cases were reported in a 3-year period, and several cases likely involved the same harbor seal. In 2 Figure 2. Harbor seal (Phoca vitulina richardii). Photo: The Marine of the cases, the bites can be attributed at least partially Mammal Center. to human behavior; in 1 case fish bait was thrown in the Download English Version: https://daneshyari.com/en/article/2614194 Download Persian Version: https://daneshyari.com/article/2614194 Daneshyari.com.